Nice effort there on the latest video. Gets off to a really good start/pace but then gets repetitive as you do the cars on the highway. Remember that viewers have been trained to see things in 2-5 second bursts. If you have a clip that is longer than that it has to be something of special importance or lots of action/activity. Or, it could be drawn out for dramatic effect, such as sombre times, etc.
Video is such an emotional medium. As the director you are bringing someone along for the story. It's hard to create long stories on car themed items. So usually I just try to tell the story, "This is how the event went". But, unless you have action like track, drifting or glamour car shots, rarely would I exceed 2 1/2 minutes. That's just a rule of thumb. All depends on how you "feel" the pace is going and if you can keep viewer interest for that long. A good test is that if you can watch it 10+ times as you are editing and still maintain interest then you are doing an ok job. If you find you are getting impatient watching something after the 3rd or 4th time then you need to trim it up.
I really like your intro. Adds a bit of "this is a production company" feel. I do that with Yamashita Productions so that people know that this is one of my videos when they see it.
I can already see the improvement in your videos so just keep working on it.
Here are a couple of my latest videos:
And some slow motion artistry testing of my newest camera. As I indicated before these are really long clips because slow motion is usually used for dramatic effect emphasizing the emotional feeling.